Projectile or the like, preferably for armor-piercing weapons, and a method of manufacturing such a projectile



1, 1965 N. E. SCHGNBERG 3,203,349

PROJECTILE OR THE LIKE, PREFERABLY FOR ARMQR-PIERCING WEAPONS, AND A METHOD OF MANUFACTURING SUCH A PROJECTILE Filed Sept. 17, 1963 A To/WVE/ United States Patent PROJECTILE OR THE LIKE, PREFERABLY FOR ARMOR-PIERCING WEAPONS, AND A METHOD OF MANUFACTURING SUCH A PROJECTILE Nils Erik Schiinberg, Kolsva, Sweden, assignor to Kohlswa Jernvel'ks Aktiebolag, Kolsva, Sweden, a Swedish jointstock company Filed Sept. 17, 1963, Ser. No. 309,493 Claims priority, application Sweden, Sept. 18, 1962, 10,0'5'3/ 62 2 Claims. (Cl. 102-52) This invention relates to a projectile or the like, preferably for armor-piercing weapons. To provide such weapons with a satisfactory piercing effect, the projectile must be given considerable weight. For this reason, the projectiles are usually made of cemented carbide or heavy metal.

For ballistic reasons, it is desired to use projectiles which are long in relation to their thickness. Long pro jectiles show, however, splintering tendency in the moment of their impact. As a result thereof, it was heretofore not possible to use projectiles having a length which exceeded their approximate circumference.

One method for reducing its splintering risk is to manufacture the projectile in several parts. This method makes, however, the manufacture more expensive at the same time as it renders the handling of the projectile more difficult. It is, for example, more complicated to grind smaller than greater parts.

According to the invention, a projectile is produced which solve the aforesaid problems and which is characterized in that it comprises two or more parts which are bonded together by one or several layers of metal binders and manufactured simultaneously in a single pressing operation, in such a manner, that the said parts are supplied in powdery state together with the binder layers to a mold and pressed in said mold.

When the front portion of the projectile is made of heavy metal and the rear portion of the projectile is made of cemented carbide, it is possible, within a volume determined by constructional and ballistic reasons, to fit a projectile of adequate weight and suitable strength into a shell or the like.

The heavy metal should have a composition containing 99-80%, preferably about 90% of tungsten and 120%, preferably about of a mixture of copper and nickel.

The cemented carbide should have a composition containing 95-75%, preferably about 85% of tungsten carbide and 5-25 preferably about of cobalt.

When the projectile is manufactured on a powder metallurgical way so that it comprises one part of cemented carbide and one part of heavy metal (with the above compositions), the different parts cannot be sintered together directly, because this would cause the formation of highly brittle compounds in the boundary layer. It is neither possible to bond the two parts together only by a layer consisting of cobalt or only by a layer consisting of a mixture of copper and nickel. In such cases the invention proposes the application of two layers, one of them which is located closest to the heavy metal consisting of copper and nickel, and the second layer which is located closest to the cemented carbide consisting of cobalt.

The invention renders it possible to manufacture a projectile of two parts and to place the joint between them directly at the transition between a rear cylindrical portion and a conical, rounded or in a similar manner shaped front portion. Hereby, grinding and similar finishing operations are facilitated. For the profiled front portion, for example a material may be chosen which is 3,263,349 Patented Aug. 31, 1965 easier to work, while in the choice of the material for the cylindrical portion greater emphasis should be laid upon its impact properties. When desired, the rear cylindrical portion may also be divided into two or more parts which are bonded together in the aforesaid manner.

The projectile according to the invention can be manufactured in a very simple manner. When the manufacture is based on the use of powder both for the different parts of the projectile and for the metal layer or layers required, the projectile can be made in a single pressing operation.

Though it is in many cases most suitable to manufacture the projectile such that it comprises a front part of heavy metal and a rear part of cemented carbide, the invention provides also adavntages when a projectile made only of cemented carbide or only of heavy metal is divided and its parts joined according to the invention. It is, namely, the main object of the said method of dividing and joining to prevent the propagation of cracks caused by the impact. Furthermore, due to the joint the projectile according to the invention is given a certain small flexibility so that it shows greater tendency to turn inwards to the plate when its impact direction on the armored plate is oblique. It is, of course, also possible and in certain cases preferable to manufacture a projectile having a front portion of cemented carbide and a rear portion of heavy metal.

For a projectile consisting only of cemented carbide, only one binder layer is required which suitably may be cobalt. The same applies to the case when the projectile is made only of heavy metal, in which case the binder layer should preferably have the same mixture of copper and nickel as it is comprised in the heavy metal.

In the aforesaid, reference was made only to cemented carbide and heavy metal. The invention may, however, also be worked with other materials suitable for projectiles. The tungsten carbide in the cemented carbide may, for example, entirely or partly be exchanged against, for example, titanium carbide or tantalum carbide.

As already mentioned, great advantages are gained by basing the manufacture of the different projectile parts and of the binder layer on powder. In certain cases, it may, however, be preferable to join a solid metal body with a sintered body made of powder.

The pressing and sintering operations of the different parts of the projectile may be carried out either in the form of pressure sintering with the help of, for example, graphite tools or in the form of hydrostatic pressing with the help of a mold adapted to be compressed on all sides. When the projectile requires working, preferably first a pre-sintering at about 900 C. is carried out so that the different parts will not be harder than to allow their relatively easy grinding or other type of working, whereafter as the final step the product is sintered fully at about 13001400 C.

The aforesaid refers only to examples showing how the invention may be applied in practice. The invention is, however, not restricted to these examples, but a plurality of modifications can be imagined Within the scope of the invention as it is defined in the following claims.

The accompanying drawing shows by way of example a projectile according to the invention, whereof an ogival front portion is designated by 1, a cylindrical rear portion by 2 and two binder layers by 3 and 4.

The front portion 1 is made of heavy metal having a composition of 90% tungsten and 10% of a mixture of copper and nickel. The rear portion 2, however, is made of cemented carbide having the composition of tungsten carbide and 15% cobalt. The layer 3 is a mixture of copper and nickel, and the layer 4 is of cobalt. The projectile shown as an example was manufactured only on the basis of powder in a single pressing operation.

What I claim is:

1. Armor-piercing projectile comprising forward and rear portions and a bonding section joining the interfaces of said Sections together, said forward and rear sections being composed of sintered material and being of uniform composition throughout the respective portions, said bonding section being composed of a metal composition which is capable of bonding to the respective portions and of preventing diffusion in the interfaces of said portions, said forward and rear portions being of different composition and said bonding section being composed of forward and rear layers which are bondable respectively to said forward and rear portions and to each other, said forward portion being composed of a mixture of a heavy metal with copper and nickel, said rear portion being composed of a mixture of a metal carbide and cobalt, the forward layer of said bonding section being composed of a mixture of copper and nickel, and the rear layer of said bonding section being composed of cobalt.

2. Armor-piercing projectile comprising forward and rear portions and a bonding section joining the interfaces of said sections together, said forward and rear sections being composed of sintered material and being of uniform composition throughout the respective portions, said bonding section being composed of a metal composition which is capable of bonding to the respective portions and of preventing diffusion in the interfaces of said portions, said forward and rear portions being of different compositions and said bonding section being composed of forward and rear layers which are bondable respectively to said forward and rear portions and to each other, said forward section being composed of a mixture of from 8099% tungsten and from 1-20% of a mixture of copper and nickel, said rear portion being'composed of a mixture of from 75-95% of tungsten carbide and from 525% cobalt, the forward layer of said bonding section being composed of copper and nickel, and the rear layer of said bonding section being composed of cobalt.

References Cited by the Examiner UNITED STATES PATENTS 2,393,648 1/46 Martin 102/52 FOREIGN PATENTS 538,276 7/41 Great Britain. 288,747 9/31 Italy.

BENJAMIN A. BORCHELT, Primary Examiner.

25 FRED C. MATTERN, JR., Examiner. 

1. ARMOR-PIERCING PROJECTILE COMPRISING FORWARD AND REAR PORTIONS AND A BONDING SECTION JOINING THE INTERFACES OF SAID SECTIONS TOGETHER, SAID FORWARD AND REAR SECTIONS BEING COMPOSED OF SINTERED MATERIAL AND BEING OF UNIFORM COMPOSITION THROUGHOUT THEE RESPECTIVE PORTIONS, SAID BONDING SECTION BEING COMPOSED OF A METAL COMPOSITION WHICH IS CAPABLE OF BONDING TO THE RESPECTIVE PORTIONS AND OF PREVENTING DIFFUSION IN TH EINTERFACES OF SAID PORTIONS, SAID FORWARD AND REAR POSITIONS BEING OF DIFFERENT COMPOSITION AND SAID BONDIND SECTIONS BEING COMPOSED OF FORWARD AND REAR LAYERS WHICH ARE BONDABLE RESPECTIVELY TO SAID FORWARD AND REAR POSITIONS AND TO EACH OTHER, SAID FORWARD PORTION BEING COMPOSED OF A MIXTURE OF A HEAVY METAL WITH A COPPER AND NICKEL, SAID REAR PORTIN BEING COMPOSED OF A MIXTURE OF A METAL CARBIDE AD COBALT, THE FORWARD LAYER OF SAID BONDING SECTION BEING COMPOSED OF A MIXTURE OF COPPER AND NICKEL, AND THE REAR LAYER OF SAID BONDING SECTION BEING COMPOSED OF COBALT. 